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Arctic sea emits methane

Source of climate-warming gas remains uncertain, but might be microbes

Atmospheric scientist Eric Kort was flying over the Arctic Ocean three years ago, monitoring readouts as onboard sensors sniffed the air. Suddenly, as the plane dipped low over some breaks in the sea’s ice cover, those instruments detected the unmistakable whiff of methane, the second most important climate-warming gas associated with human activities.

“This was unexpected,” says Kort, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif. On four more excursions north of the Beaufort and Chukchi seas through April 2010 — always in winter or early spring — the plane’s sensors detected the same taint of methane in very-low-altitude air over broken patches of ice, Kort and collaborators report online April 22 in Nature Geoscience.

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